Conventionally, surface acoustic wave resonators using surface acoustic waves (SAW) have been widely used in electronic apparatuses.
With the recent spread of portable devices, a decrease in the size of a surface acoustic wave resonator used therein has been required. With the decrease in the size of the surface acoustic wave resonator, there is a problem in that a decrease in Q value or an increase in CI value is caused and thus the characteristics of the surface acoustic wave resonator cannot be satisfactorily obtained.
As a countermeasure, for example, PTL 1 discloses a technique of enhancing the Q value by reducing a ratio (a line width ratio or a line occupying ratio) of an electrode finger width to an electrode finger pitch in a comb-like electrode from the center of the comb-like electrode to both edges thereof using a 41°-rotated Y-cut lithium niobate substrate.